A stereo camera device is a device that simultaneously receives images from two cameras. The stereo camera device calculates distances from left and right images to an object, and thus may be used to obtain a three-dimensional (3D) image.
Such stereo cameras may be aligned on the same row, and may extract a depth of an object on the assumption that the stereo cameras are aligned on the same row. However, when a tolerance occurs in the production process or positions of the cameras deviate from each other during use, the stereo cameras may not be aligned on the same row. Specifically, it is easy for positions of stereo cameras mounted on a vehicle to be deviated from each other due to an impact and the like.
Thus, in order to obtain an accurate depth extraction result, a rectification process in which left and right images are changed to be like images photographed by two cameras aligned on the same row is required.
A reference point is required for rectification. Generally, the reference point may be extracted from a chess board or a 3D object. However, there are problems in that a space is required to install the chess board or the 3D object and the reference point is difficult to be recognized at night or in places such as a basement and the like, in which an amount of light is insufficient.
Therefore, a method of performing rectification without time and space constraints is required.